ITU-T SERIES K SUPP 25 PDF

Two-pair and four-pair Ethernet test circuits are defined for equipment in [ITU-T K.44] and for surge protective devices (SPDs) in [ITU-T K.117]. This Supplement proposes 10 Mb/s, 1 km single-pair Ethernet (SPE) test circuits and test levels for SPDs. As 10 Mb/s, 1 km SPE deployment is currently minimal, there is an absence of field data to support resistibility requirements. These proposals are made from extrapolation of existing communications link data and published papers on the subject. The following factors are considered:

• Overvoltage and overcurrent threats;

• Threat coupling;

• Threat levels;

• Threat modes and circuit occurrence; common mode or differential mode occurring on the cable conductors or any cable screening;

• Appropriate components or devices and techniques to mitigate threat levels down to a level that prevents equipment component or insulation failure;

• Ethernet circuit configurations and maximum electrical signal, insulation withstand and powering values to determine the best placement of mitigation measures;

• Ethernet SPE SPD testing.